1. Field of the invention
The invention relates to a method for making contacts for use with a gas-blast circuit breaker.
2. Description of the Prior Art
German Offenlegungsschrift No. 2,215,929 discloses a contact system for use with a gas-blast circuit breaker wherein an arc is drawn in the gap between the contacts when the breaker is interrupted under load. The aforesaid contact system is further provided with means for providing magnetic forces which accelerate formation of the arc independently of the pressurized-gas flow which is set in motion during the interruption process. The aforesaid means is in the form of slots arranged in the end faces of the contacts. These slots, in turn, are formed by recesses which initially run level and then at an angle to the axis of the contacts so as to enter the inner opening of the contacts tangentially. In this manner, the quantity of quenching gas which is carried into the gap between the two contacts during the interrupting process of the breaker is better utilized. Also to prevent the slots from disturbing the gas flow in the vicinity of the end faces of the contacts, the slots are filled with an arc-resistant insulating material.
Typically, the above-described contact system is manufactured by using material removing tools, such as milling or sawing tools, to form slots along a portion